Magic Modeling Compound

Magic Modeling Compound
What are some good polymers for use in a primary school class?

I'm trying to do a lesson on composite materials short fiber for a fifth-grade class-4. I have the following requirements: 1. If cure / set up quickly (less than four hours to make a 3 mm thick film) 2. Should be reasonably elastic (deformation will be measured with a ruler) 3. If you have the ability to substances mixed in it while you are creating (Such as coir yarn, fishing nylon threads, etc) 4. In case of non-toxic compounds We have tried to fill, they have worked, if not take so long to dry. We Crayola Model Magic tried, but it is too brittle when dry. We are still trying different concentrations of gelatin, to the extent that tear too ease. We will also test the agar jelly powder. Any other suggestions?

Try polyurethane as Gorilla Glue, amazing stuff and I think that it meets all your needs.